Heart health to benefit from GM oils

[Rick Roush <rick.roush@adelaide.edu.au>]

Heart health to benefit from GM oils

CSIRO
Monday, 28 May 2001

The world's first cotton plants genetically modified to produce healthier
cooking oils and margarines have been developed by CSIRO Plant Industry.

Cottonseed oil is already used extensively as an ingredient in margarines
and cooking oils, particularly in the food service sector.

However, to make it suitable for these uses it is generally subjected to a
process known as 'hydrogenation' which can produce cholesterol-raising
trans fatty acids as a by-product.

"Oil from our improved cottonseed is suitable for cooking purposes without
the need for hydrogenation," says Dr Allan Green, leader of the research
team.

"Products made from these oils will be healthier because they will not
contain trans fatty acids."

To produce the new oils, the scientists 'switched off' genes in cottonseed
that normally convert oleic acid, a monounsaturated fatty acid, into
polyunsaturated fatty acids. Polyunsaturates are nutritionally valuable,
but break down under extreme heat, making them unsuitable for cooking
uses.

"The hydrogenation process converts the polyunsaturates back into
monounsaturates, but we have prevented their formation in the first
place," says Dr Qing Liu, the scientist who genetically modified the
cotton.

"By turning off the gene that produces polyunsaturates we have produced
for the first time an inherently high-oleic cottonseed oil.

"We haven't added any foreign genes to the cotton to achieve this, but
have reintroduced a very small amount of the cotton plant's own DNA."

The healthy high oleic cottonseed oil will remain stable under high
temperatures, making it a suitable replacement for hydrogenated oils and
saturated oils in food service applications.

In a related development, the CSIRO research team has also successfully
used gene technology to alter the proportions of saturated fatty acids in
cottonseed oil. Saturated fatty acids provide the solid properties that
make cottonseed oil useful in margarine production.

About a quarter of cottonseed oil is made up of two saturated fatty acids,
called palmitate and stearate. Conventional cottonseed contains mostly
palmitate, with small amounts of stearate. Nutritionists believe that
stearate does not raise blood cholesterol, but palmitate does.

Dr Liu has modified the cottonseed so that it produces stearate instead of
palmitate, making it a healthier product for margarines.

"Preliminary testing of the high oleic and high stearic oils will be
undertaken by Food Science Australia at the end of the year," says Dr
Green.

"Following successful completion of the product testing and approvals from
the Office of the Gene Technology Regulator, work will begin on developing
commercial varieties of the genetically modified cottons."

The first field trials could commence in 2002. If all progresses well,
commercial varieties could be available to growers by 2004 with the first
commercial harvest in 2005.

"This development will ultimately help the Australian food industry
replace our $50 million annual imports of palm oils with healthier,
locally produced oils," says Dr Green.

"The improvement in nutritional value of our food oils is an example of
how gene technology can be used to provide consumer benefits not
achievable with conventional breeding approaches."